Server-side only mod.
It has a command: /setrenderdistance, /srd, or whatever and is used like this:
/srd 5 means the server will send you only chunks in a renderdistance of 5
purpose: people with slow internet will set themselves a lower renderdistance, so they can still play normally, while people with fast internet can see more
config: maximum, so you cant lag the server by accidentally/intentionally typing /srd 1000 or whatever